Naturally, I'd go with the original one, but I understand that the Cast might say they could be mistaken for Lightning matoran (Which I don't believe, despite the example done by @Asriel)I think the other color scheme is too dark and we are unable to see detail, even making the mask recognition difficult. And then again, they could be mistaken for Nahoan matorans aswell.

So, no sand pirates then? I think the idea is a lot more distinct and fitting, I mean there would be a lot more caravans in the desert, and the lack of resources would be a logical reason for the piracy, Plus sand ships are cooler than regular ships.